1. Field of the Invention
The present invention relates to a liquid crystal display device. More particularly, the present invention relates to a transflective liquid crystal display device.
2. Discussion of the Related Art
A liquid crystal display device may be classified into a transmissive liquid crystal display device, which uses a backlight unit as a light source, and a reflective liquid crystal display device that uses natural light as a light source.
The transmissive liquid crystal display uses a backlight unit as a light source, thereby displaying a bright image in a dark environment. However, since the transmissive liquid crystal display uses the backlight unit, power consumption is increased. Since the reflective liquid crystal display device uses natural light in environment instead of the backlight unit, power consumption is reduced. However, the reflective liquid crystal display device cannot be used in a dark environment.
In order to solve theses problems, a transflective liquid crystal display device has been proposed. Since the transflective liquid crystal display device has only the advantages of the transmissive and reflective liquid crystal display devices, the transflective liquid crystal display device can be used in a dark environment while consuming relatively low power.
The transflective liquid crystal display device includes a reflection part and a transmission part. Further, the transflective liquid crystal display device additionally has a process of forming a reflection sheet in the reflection part, as compared with a typical transmissive liquid crystal display.
According to the transflective liquid crystal display device, the reflection part and the transmission part can be recognized by turning backlight on or off. In general, a cell gap of the transmission part is approximately twice as great as that of the reflection part.
Liquid crystal provided in the transflective liquid crystal display device according to the prior art has a narrow viewing angle due to birefringence characteristics thereof. The liquid crystal adopts an ECB (electrically controlled birefringence) mode using interference between ordinary ray and extraordinary ray of incident light. However, in the ECB mode, since a polarization state may vary depending on a dual cell gap between the reflection part and the transmission part, light transmittance may deteriorate. In order to compensate for deterioration of the light transmittance, the ECB mode transflective liquid crystal display device requires at least four compensation films.
Thus, the related art transflective liquid crystal display device must have an ECB mode liquid crystal in order to improve the viewing angle characteristics. However, since the ECB mode liquid crystal requires an additional compensation film, the manufacturing cost of the related art transflective liquid crystal display device is increased.